1. Field of the Invention
The present invention relates to modular plugs and modular jacks and, particularly, to a modular plug for directing a plurality of twist pairs of core wires into the opening of a modular jack for electrical connection and modular jack for use with a modular plug for electrical connection with a plurality of core wires.
2. Description of the Related Art
Modular plugs and modular jacks are used for telephone sets or local area networks. A modular plug is connected to a plurality of core wires of a cable and plugged into equipment. A modular jack is mounted on the equipment to receive the modular plug.
A guide member is provided in the modular plug to arrange the core wires of a cable. An example of the guide member is shown in Japanese patent application Kokai No. 7937/96. The guide member is made from plastic, and the core wires are arranged horizontally at regular intervals. The cable has a plurality of twist pairs, each of which consists of a pair of twisted core wires, to prevent generation of noise by the alternating magnetic fields.
A contact terminal is attached to each of the core wires arranged by the guide member to receive an electrical signal from the core wire and transmit it to the modular jack. A substantially rectangular contact terminal is disclosed by the above Japanese patent application, and a blade-like contact terminal is disclosed in Japanese patent application Kokai No. 1621756/96. These contact terminals are arranged at regular intervals such that adjacent contact terminals overlap each other in the entire area.
Also, a plurality of contact terminals are provided in the modular jack. When the modular plug is plugged into the modular jack, the contact terminals are brought into contact each other. The contact terminals of the modular jack are arranged at regular intervals such that adjacent contact terminals overlap each other.
The current running in a circuit or terminal is induced by electromagnetic or static coupling to flow in another circuit to thereby cause crosstalk. The crosstalk interferes with signal transmission in the circuit or terminal, causing noise or other problems. Accordingly, it is necessary to reduce the crosstalk.
When the core wires are arranged horizontally at regular intervals, the twist pairs are prone to electromagnetic coupling and hardly receive shielding effect. Consequently, crosstalk can occur between the twist pairs. Where the guide member is made from a plastic, the same problem takes place. Where the contact terminals are arranged such that they overlap each other, crosstalk can occur between the contact terminals.
Where adjacent contact terminals of the modular jack overlap each other, crosstalk takes place between the contact terminals. Where the contact terminals of the modular jack form pairs corresponding to the twist pairs of the modular plug, crosstalk can occur between the paris.